OBJECTIVES: To characterize the efflux pump encoded by the gene Rv2333c from Mycobacterium tuberculosis, and assess its contribution to intrinsic antibiotic resistance using Mycobacterium bovis BCG as a model organism. METHODS: Firstly, the Rv2333c gene was expressed from a multicopy plasmid in M. bovis BCG. Secondly, the gene was inactivated in the chromosome of M. bovis BCG. Antibiotic susceptibility tests and tetracycline uptake/efflux experiments were carried out with the strains mentioned above. RESULTS: When the Rv2333c gene was inactivated in the M. bovis BCG chromosome, there was a decrease in the MIC values of spectinomycin and tetracycline, and an increase in [3H]tetracycline accumulation. When the Rv2333c gene was cloned into a multicopy plasmid, there was an increase in the MIC values of spectinomycin and tetracycline, and a decrease in [3H]tetracycline accumulation. These results indicate that both antibiotics are substrates of the Rv2333c efflux pump, which has been named Stp, for Spectinomycin Tetracycline efflux Pump. CONCLUSIONS: The Rv2333c efflux pump (Stp protein) of M. tuberculosis contributes to intrinsic spectinomycin and tetracycline resistance.
Contribution of the Rv2333c efflux pump (the Stp protein) from Mycobacterium tuberculosis to intrinsic antibiotic resistance in Mycobacterium bovis BCG
DE ROSSI, EDDA;
2007-01-01
Abstract
OBJECTIVES: To characterize the efflux pump encoded by the gene Rv2333c from Mycobacterium tuberculosis, and assess its contribution to intrinsic antibiotic resistance using Mycobacterium bovis BCG as a model organism. METHODS: Firstly, the Rv2333c gene was expressed from a multicopy plasmid in M. bovis BCG. Secondly, the gene was inactivated in the chromosome of M. bovis BCG. Antibiotic susceptibility tests and tetracycline uptake/efflux experiments were carried out with the strains mentioned above. RESULTS: When the Rv2333c gene was inactivated in the M. bovis BCG chromosome, there was a decrease in the MIC values of spectinomycin and tetracycline, and an increase in [3H]tetracycline accumulation. When the Rv2333c gene was cloned into a multicopy plasmid, there was an increase in the MIC values of spectinomycin and tetracycline, and a decrease in [3H]tetracycline accumulation. These results indicate that both antibiotics are substrates of the Rv2333c efflux pump, which has been named Stp, for Spectinomycin Tetracycline efflux Pump. CONCLUSIONS: The Rv2333c efflux pump (Stp protein) of M. tuberculosis contributes to intrinsic spectinomycin and tetracycline resistance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
